Semiconductor device and method for manufacturing the same

ABSTRACT

A semiconductor device having a through electrode excellent in performance as for an electrode and manufacturing stability is provided. There is provided a through electrode composed of a conductive small diameter plug and a conductive large diameter plug on a semiconductor device. A cross sectional area of the small diameter plug is made larger than a cross sectional area and a diameter of a connection plug, and is made smaller than a cross sectional area and a diameter of the large diameter plug. In addition, a protruding portion formed in such a way that the small diameter plug is projected from the silicon substrate is put into an upper face of the large diameter plug. Further, an upper face of the small diameter plug is connected to a first interconnect.

This application is based on Japanese patent application NO.2004-108304, the content of which is incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention related to a semiconductor device and a method formanufacturing the same.

2. Related Art

In recent years a semiconductor device necessitates to be lightweight,thin, and short sized, and a high performance. In the semiconductordevice such as multi-chip package or the like, realizing high densityinterconnect, miniaturization of a logic chip and capacity increase of amemory is aggressively promoted.

As for one corresponding medium coping with such proposals, it is triedthat realizing high density interconnect or the like is achieved uponproviding a through electrode on the semiconductor substrate. A throughelectrode as for the conventional one is described in the JapaneseLaid-Open Patent Publication No. 2000-311982.

The Japanese Laid-Open Patent Publication No. 2000-311982 discloses thesemiconductor device having the through electrode. Configuration of thethrough electrode is that an intermediate insulating layer is providedon an inner circumferential surface of the through hole penetrating thesemiconductor chip substrate, and a conductive layer is filled in thethrough hole inside the intermediate insulating layer. According to theJapanese Laid-Open Patent Publication No. 2000-311982, if theconfiguration is used, this makes it possible to form pluralsemiconductor chip substrates three-dimensionally with high density.

In addition, although a technical field is different, there is atechnique described in “Wafer Process and Issue of Through Electrode inSi wafer Using Cu Damascene for Three Dimensional Chip Stacking” ByMasataka Hoshino and other five members, 2002, Proceedings of theInternational Interconnect Technology Conference p. 75 to 77 (MasatakaHoshino et. al,), as for a technique to remove the semiconductorsubstrate and a metal film simultaneously. The Masataka Hoshino et. al,describes the semiconductor substrate including the process in whichgrinding a rear surface is performed, after forming an electrode, thatis described later.

SUMMARY OF THE INVENTION

On the other hand, the through electrode described in the JapaneseLaid-Open Patent Publication No. 2000-311982 has structure in whichthick through electrode is penetrated through the semiconductor chipsubstrate, so that it is not possible to provide interconnect or thelike on a region at which the through electrode is formed. For thisreason, it has now been discovered that integration density of theinterconnect or the like decreases, therefore, there is still room forfurther improvement on realizing high density interconnect. Further,there is a fear that reliability of the element deteriorates at the timethe through electrode is formed because the through electrode is formedafter forming elements.

According to the present invention, there is provided a semiconductordevice comprising: a semiconductor substrate; an insulating layerprovided on a main surface of the semiconductor substrate and having aconductive component therein; and a through electrode penetrating thesemiconductor substrate and connected to the conductive component;wherein the through electrode including: a first conductive plugconnected to the conductive component; and a second conductive plugprovided in the semiconductor substrate and connected to the firstconductive plug, the second conductive plug has a cross sectional arealarger than a cross sectional area of the first conductive plug.

In the semiconductor device of the present invention, the firstconductive plug with smaller cross sectional area than the secondconductive plug is disposed at the side of the main face, therefore, itis possible to enhance integration density of the interconnect in thevicinity of the through electrode. For this reason, the configuration issuitable for miniaturization.

According to the present invention, there is provided a semiconductordevice comprising a semiconductor substrate, an insulating layerprovided on a main face of the semiconductor substrate, and a throughelectrode, which penetrates the semiconductor substrate, connecting aconductive component provided on an inside of the insulating layer,wherein the through electrode comprises a first conductive plugconnecting the conductive component, and a second conductive plug, whichis provided in the semiconductor substrate and which has a crosssectional area larger than a cross sectional area of the firstconductive plug, involving a part of the first conductive plug.

In the present specification, a main face is of a face of asemiconductor substrate on which semiconductor elements are formed. Inaddition, although the second conductive plug is provided on thesemiconductor substrate, a part of the second conductive plug may residewithin the insulating film provided on the main face.

In the semiconductor device of the present invention, a part of thefirst conductive plug is involved in the second conductive plug. Forthis reason, anchor effect is suitably obtained, so that configurationof these plugs is excellent in adhesion. Furthers the configurationreduces contact resistance between these plugs. Further, the firstconductive plug with small cross sectional area is disposed at the sideof the main face, therefore, it is possible to enhance integrationdensity of the interconnect in the vicinity of the through electrode.For this reason, the configuration is suitable for miniaturization.

According to the present invention, there is provided a semiconductordevice comprising a semiconductor substrate, a transistor formed layerprovided on a main face of the semiconductor substrate, an interconnectlayer provided on an upper portion of the transistor formed layer, anupper interconnect layer provided on an upper portion of theinterconnect layer, and a through electrode penetrating the transistorformed layer and the semiconductor substrate, wherein the throughelectrode comprises a first conductive plug connecting an interconnectformed in the interconnect layer and provided in the transistor formedlayer, and a second conductive plug, which is provided in thesemiconductor substrate and which has a cross sectional area larger thana cross sectional area of the first conductive plug, connecting thefirst conductive plug.

In the semiconductor device of the present invention, the firstconductive plug is connected to the interconnect layer coated to theupper interconnect layer. Further, configuration is that the crosssectional area of the first conductive plug is smaller than the crosssectional area of the second conductive plug. For this reason, theconfiguration makes it possible to enhance integration of an upper layerof the interconnect layer and the elements. Accordingly, thesemiconductor device of the present invention realizes configurationsuitable for miniaturization. It should be noted that, in the abovesemiconductor device, the first conductive plug is provided in thetransistor formed layer, however, also it may be suitable that a part ofthe first conductive plug reside in the substrate. In addition, thesecond conductive plug is provided on the semiconductor substrate,however, also it may be suitable that a part of the second conductiveplug reside in the insulating film.

In the semiconductor device of the present invention, it may be suitableto adopt configuration in which the upper interconnect layer connects tothe interconnect layer. The semiconductor device of the presentinvention can improve integration density of the interconnect providedon the interconnect layer and the upper interconnect provided on theupper interconnect layer even the case of configuration where the upperinterconnect layer is connected to the through electrode via theinterconnect layer.

In the semiconductor device of the present invention, it may be adoptedconfiguration where the first conductive plug is involved in the secondconductive plug. Owing to this, the anchor effect can be surelyobtained. For this reason, adhesion of these plugs can be improved.Further, it is possible to realize configuration where contactresistance between these plugs is reduced.

In the semiconductor device of the present invention, it may suitably beadopted configuration where a part of the plurality of the firstconductive plugs is involved in the second conductive plug. Owing tothis, it is possible to further surely obtain the anchor effect. Forthis reason, adhesion of these plugs can be further improved. Further,it is possible to realize configuration where contact resistance betweenthese plugs is further reduced.

In the semiconductor device of the present invention, the secondconductive plug may be formed across vicinity of the main face of thesemiconductor substrate from a rear surface of the semiconductorsubstrate. In addition, in the semiconductor device of the presentinvention, the second conductive plug may be positioned at a portionlower than the main face of the semiconductor substrate. In such a wayas above, the integration density of the element or the interconnect onthe semiconductor substrate can be further improved.

In the semiconductor device of the present invention, it may be suitableto adopt configuration where a part of the first conductive plug is putinto the second conductive plug. For this reason, it is possible tofurther surely improve adhesive of both plugs.

In the semiconductor device of the present invention, it may be suitableto adopt configuration where the second conductive plug comes intocontact with the semiconductor substrate via an insulating film. Forthis reason, it is possible to realize configuration with manufacturingeasiness. Further, it is possible to decrease parasitic capacitance. Forinstance, in the present invention, the insulating film can be made withan electrodeposited insulating film.

In the semiconductor device of the present invention, it may be suitableto adopt configuration where the second conductive plug is projectedfrom a rear surface of said semiconductor substrate. Therefore, it ispossible to realize configuration being further excellent inmanufacturing stability.

In the semiconductor device of the present invention, it may be suitableto adopt configuration where a cylindrical ring shaped insulating bodyis disposed on an outer periphery of a side face of the secondconductive plug. For this reason, it is possible to reduce surelyparasitic capacitance.

In the semiconductor device of the present invention, it may be suitableto adopt configuration where a cross sectional area of the throughelectrode in the main face of the semiconductor substrate is smallerthan a cross sectional area of the through electrode in a rear surfaceof the semiconductor substrate. Owing to this, it is possible to enhanceintegration density of the interconnect formed on an upper portion ofthe main face.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming a first hole ata main surface of a semiconductor substrate; forming a first conductiveplug in the first hole; forming a second hole at a rear surface of thesemiconductor substrate to expose the first conductive plug therein; andforming a second conductive plug in the second hole to be connected tothe first conductive plug.

According to the method, it is possible to stably manufacture thesemiconductor device with simple process that has a through electrodethat is excellent in adhesion between the first conductive plug and thesecond conductive plug.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming an opening at amain surface of a semiconductor substrate; filling the opening with aninsulating material; forming an insulating layer on the semiconductorsubstrate; forming a first hole penetrating the insulating layer toexpose a part of the insulating material in a bottom of the first hole;forming a first conductive plug in the first hole; removing a part ofthe semiconductor substrate at a rear surface of the semiconductorsubstrate to expose the insulating material; removing the insulatingmaterial to form a second hole, a part of the first conductive plug isexposed in the second hole; and forming a second conductive plug in thesecond hole to be connected to the part of first conductive plug exposedin the second hole.

According to the method, it is possible to further stably manufacturethe semiconductor device having the through electrode that is excellentin adhesion between the first conductive plug and the second conductiveplug.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming a first hole ata side of a main face of a semiconductor substrate, forming a barrierfilm made of insulating materials on an inner wall of the first hole,embedding a first metal film so as to embed an inside of the first hole,forming a first conductive plug on an inside of the first hole whileremoving the first metal film formed on an outside of the first hole,exposing a part of the first conductive plug on the inside of a secondhole while forming the second hole upon removing the semiconductorsubstrate selectively from a rear surface side, exposing the first metalfilm while removing at least a part of the barrier film exposed, andforming a second conductive plug involving a part of the firstconductive plug while causing a second metal film to grow so as to embedthe second hole after exposing the first metal film.

According to this method, it is possible to stably manufacture thesemiconductor device with simple process that has a through electrodethat is excellent in adhesion between the first conductive plug and thesecond conductive plug.

In the present invention, the first conductive plug includes the firstmetal film and the barrier film. In addition, in the present invention,the first metal film may include the barrier metal film.

In a method for manufacturing the semiconductor device of the presentinvention, the method comprises forming a cylindrical ring shapedinsulating body by embedding an insulating body on an inside of a hole,while forming a cylindrical ring shaped hole by selectively removing thesemiconductor substrate from a side of the main face before forming thefirst hole; forming the first hole comprises forming the first holewhile removing a part of an inside region of the cylindrical ring shapedinsulating body of the semiconductor substrate; and forming the secondhole comprises forming the second hole while removing at least a part ofan inside region of the cylindrical ring shaped insulating body of thesemiconductor substrate. In such a way as above, it is possible tosurely obtain the semiconductor device in which generation of theparasitic capacitance is suppressed.

In the method for manufacturing the semiconductor device of the presentinvention, forming the first hole may comprise forming the first holewhile selectively removing an insulating film and the semiconductorsubstrate, after forming the insulating film on a side of the main faceof the semiconductor substrate. In such a way as above, it is possibleto stably obtain the semiconductor device of configuration in which thefirst conductive plug connects to the interconnect of an upper portionof the insulating film.

According to the present invention, there is provided a method formanufacturing a semiconductor device comprising: forming an insulatingplug by embedding an insulating body into an inside of a hole, whileforming the hole by removing a semiconductor substrate selectively froma side of a main face of the semiconductor substrate; forming a firsthole from which a part of the insulating plug is removed selectively ona side of the main face of the semiconductor substrate; embedding afirst metal film so as to embed an inside of the first hole; forming afirst conductive plug on the inside of the first hole, while removingthe first metal film formed on an outside of the first hole; removingthe semiconductor substrate selectively from a side of a rear surface ofthe semiconductor substrate; exposing a part of the first conductiveplug into an inside of a second hole, while forming the second hole byremoving the insulating plug selectively after removing thesemiconductor substrate; exposing the first metal film, while removingat least a part of the first conductive plug exposed; and forming asecond conductive plug involving a part of the first conductive plug,while causing the second metal film to grow so as to embed the secondhole after exposing the first metal film.

According to the method, it is possible to further stably manufacturethe semiconductor device having the through electrode that is excellentin adhesion between the first conductive plug and the second conductiveplug.

In the method for manufacturing the semiconductor device of the presentinvention, forming the first hole may comprise forming the first hole byremoving an insulating film and the insulating plug selectively, afterforming the insulating film on a side of the main face of thesemiconductor substrate. In such a way as above, it is possible tostably obtain the semiconductor device of configuration in which thefirst conductive plug connects to the interconnect of an upper portionof the insulating film.

In the method for manufacturing the semiconductor device of the presentinvention, forming the second hole may comprise forming a hole whosecross sectional area is larger than the first hole. In such a way asabove, it is possible to further surely involve a part of the firstconductive plug into the second conductive plug.

In the method for manufacturing the semiconductor device, the method formanufacturing the semiconductor device may comprise forming aninterconnect layer having an interconnect connecting to the firstconductive plug on an upper portion of the main face, after forming thefirst conductive plug. In such a way as above, it is possible to enhancethe integration density of the interconnect connecting to the firstconductive plug and the interconnect of the same layer. Owing to this,it is possible to manufacture stably the semiconductor device with highintegration density of the interconnect. In addition, in the method formanufacturing the semiconductor device of the present invention, themethod for manufacturing the semiconductor device may comprise formingan upper interconnect connecting the interconnect on an upper portion ofthe interconnect layer. In such a way as above, it is possible tomanufacture stably a multilayered semiconductor device in which theintegration density of the upper interconnect residing on an upper layerthan the interconnect layer is high.

In the method for manufacturing the semiconductor device of the presentinvention, the method for manufacturing the semiconductor device maycomprise providing an insulating layer on an upper portion of the mainface of the semiconductor substrate before forming the first hole; andforming the first conductive plug may comprise forming a connection plugconnecting to a transistor element at the same time as the firstconductive plug on an inside of the insulating layer. Owing to this, itis possible to obtain the semiconductor device with more simple process.

It should be noted that it is effective as the embodiment of the presentinvention even though these respective constitution are combinedarbitrarily, or representation of the present invention is converted inconnection with its method, device or the like.

For instance, in the present invention, the method for manufacturing thesemiconductor device may comprise making to adhere selectively aninsulating material on a region except for the first conductive plug ofan inner face of the second hole, before exposing the first metal film,after exposing a part of the first conductive plug. In such a way asabove, it is possible to manufacture the semiconductor device that isexcellent in insulating characteristics of a surface of the secondconductive plug by a simple process.

In the method for manufacturing the semiconductor device of the presentinvention, the insulating material may be electrodeposited material. Insuch a way as above, it causes the insulating material to adhere to aregion of an inner face of the second hole except for the firstconductive plug with further high selectivity.

In the method for manufacturing the semiconductor device of the presentinvention, the electrodeposited material may be an electrodepositedpolyimide. In such a way as above, it is possible to enhance durabilityof the insulating material to processing in this process and afterward.Consequently, it is possible to stably manufacture the semiconductordevice with further high yield.

In addition, in the present invention, embedding the first metal filmmay comprise forming a barrier metal film on an inner wall of the firsthole. In addition, in the present invention, the first metal film can beformed with a multilayered film including the barrier metal film. Insuch a way as above, it is possible to further surely suppress diffusionof conductive materials composing the first conductive plug toward thesemiconductor substrate.

As illustrated above according to the present invention, the throughelectrode is composed of the first conductive plug provided on the mainface side and the second conductive plug whose cross sectional area islarger than that of the first conductive plug of the semiconductorsubstrate, therefore, there is provided the semiconductor device havingthe through electrode that is excellent in performance as for theelectrode and the manufacturing stability.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, advantages and features of the presentinvention will be more apparent from the following description taken inconjunction with the accompanying drawings, in which:

FIG. 1 is a cross-sectional view schematically showing configuration ofa semiconductor device according to a present embodiment;

FIGS. 2A to 2D are cross-sectional views illustrating a manufacturingprocess of the semiconductor device of FIG. 1;

FIG. 3 is a cross-sectional view schematically showing configuration ofthe semiconductor device according to the present embodiment;

FIGS. 4A to 4D are cross-sectional views illustrating the manufacturingprocess of the semiconductor device of FIG. 3;

FIG. 5 is a cross-sectional view schematically showing configuration ofthe semiconductor device according to the present embodiment;

FIGS. 6A to 6D are cross-sectional views illustrating the manufacturingprocess of the semiconductor device of FIG. 5;

FIGS. 7A to 7C are views schematically showing configuration of athrough electrode;

FIGS. 8A and 8B are cross-sectional views schematically showingconfiguration of the through electrode;

FIGS. 9A and 9B are plan views illustrating a method for manufacturingthe semiconductor device according to the present embodiment;

FIG. 10 is a cross-sectional view schematically showing configuration ofthe semiconductor device according to the present embodiment;

FIG. 11 is a cross-sectional view schematically showing configuration ofthe semiconductor device according to the present embodiment; and

FIGS. 12A and 12B are cross-sectional views schematically showingconfiguration of the through electrode according to the presentembodiment.

DETAILED DESCRIPTION OF THE INVENTION

The invention will now be described herein with reference toillustrative embodiments. Those skilled in the art will recognize thatmany alternative embodiments can be accomplished using the teachings ofthe present invention and that the invention is not limited to theembodiments illustrated for explanatory purposed.

Hereinafter, there will be described an embodiment of the presentinvention while referring to the drawings. In the whole drawings, thesame symbol is attached to the same component, and detailed descriptionwill be omitted appropriately in the following explanation. Further, inthe following embodiments, a main face side of the semiconductorsubstrate is set to an upper (front surface) side of the semiconductordevice, and a rear surface side of the semiconductor substrate is set toa lower (rear surface) side of the semiconductor device.

First Embodiment

FIG. 1 is a cross-sectional view schematically showing configuration ofa semiconductor device according to the present embodiment. Thesemiconductor device 100 of FIG. 1 has a layered structure formed with asilicon substrate 101, an etching stopper film 109, a lowermost layerinsulating film 111, and a first interconnect layer insulating film 113.The semiconductor device 100 is provided with a through electrode 135penetrating the silicon substrate 101, the etching stopper film 109 andthe lowermost layer insulating film 111.

A MOS transistor composed of a diffusion layer 105, a gate electrode 107and the like, and an isolation film 103 is formed on a main face of thesilicon substrate 101. The lowermost layer insulating film 111 is formedso as to embed the MOS transistor and the isolation film 103. Theetching stopper film 109 is provided in the lowermost insulating film111 in such a way as to come into contact with an upper face of thesilicon substrate 101 and the gate electrode 107. In addition, there isalso provided a connection plug 123 in the lowermost insulating film 111to connect to the diffusion layer 105.

There is provided a first interconnect 121 and a connection plug 122 toelectrically connect to the first interconnect 121 in the firstinterconnect layer insulating film 113. In addition, on an upper portionof the connection plug 122, a pad 125 to electrically connect to theconnection plug 122 and a bump 127 to electrically connect to the pad125 are formed in this order.

The through electrode 135 has a conductive small diameter plug 119 and aconductive large diameter plug 131. The respective cross sectional areaand the diameter of the small diameter plug 119 are larger than thecross sectional area and the diameter of the connection plug 123, andsmaller than the cross sectional area and the diameter of the largediameter plug 131. Further, a protruding portion 141, in which the smalldiameter plug 119 protrudes from the silicon substrate 101, is put intoan upper face of the large diameter plug 131.

A diameter of the small diameter plug 119 can be set to, for instance, 1to 5 μm. Further, the small diameter plug 119 can be set to aconfiguration where the small diameter plug 119 is put into the siliconsubstrate 101 to a depth of 20 to 50 μm. Further, length of theprotruding portion 141 put into the large diameter plug 131 is set to,for instance, 1 to 50 μm. In addition the diameter of the large diameterplug 131 is set to, for instance, 10 to 1000 μm.

The small diameter plug 119 penetrates the etching stopper film 109 andthe silicon substrate 101 in this order from the upper face of thelowermost-layer insulating film 111, so that a leading end of the smalldiameter plug 119, which is exposed to the outer portion of the siliconsubstrate 101, becomes a protruding portion 141. The upper face of thesmall diameter plug 119 comes into contact with the first interconnect121, which has a bottom face within the same flat surface as a bottomface of the first interconnect layer insulating film 113, so thatelectrical connection between the small diameter plug 119 and the firstinterconnect 121 is secured. A side face of the small diameter plug 119is coated with SiN film 137 except for the protruding portion 141.

Further, the large diameter plug 131 is formed toward the main face fromthe rear surface of the silicon substrate 101. The upper face of thelarge diameter plug 131 is positioned at the lower portion than theupper face of the silicon substrate 101. There is provided anelectrodeposited insulating film 129 on the bottom face and side face ofthe large diameter plug 131, and on the rear surface of the siliconsubstrate 101. Further, a surface of the large diameter plug 131 iscoated with a plating film 133.

Although material of the small diameter plug 119 is not particularlylimited, it is possible to use, for instance, W (tungsten). Owing tothis, diffusion to the silicon substrate 101 is suitably suppressed. Inaddition, although material for the large diameter plug 131 and theplating film 133 are not particularly limited, but the materials can berespectively set to, for instance, Ni and Au.

Next, there will be described a method for manufacturing thesemiconductor device 100. FIGS. 2A to 2D are sectional viewsschematically showing the manufacturing process of the semiconductordevice 100 shown in FIG. 1.

Firstly, the gate electrode 107, the diffusion layer 105 and theisolation film 103 are formed on the silicon substrate 101. Theisolation film 103 is set to, for instance, STI (shallow trenchisolation). After that, the etching stopper film 109 and thelowermost-layer insulating film 111 are formed in this order on theentire surface of the upper face of the silicon substrate 101.

At this time, as the etching stopper film 109, for instance, SiN film of50 nm is formed by plasma CVD technique. Further, as the lowermost-layerinsulating film 111, for instance, SiO₂ film of 400 nm is formed byplasma CVD technique. Or, as the lowermost-layer insulating film 111, itmay suitably be formed the multilayered film in such a way that L-Ox™film of 300 nm to be a low dielectric constant interlayer insulatingfilm is formed by an application technique, and SiO₂ film of 100 nm isformed on an upper face of the L-Ox™ film.

Next, an antireflection film and photoresist are applied in this orderon the lowermost-layer insulating film 111, upon using photolithographytechnique, resulting in forming resist pattern (not shown in thedrawings) having an opening corresponding to shape of the small diameterplug 119. A position where the small diameter plug 119 should beprovided is opened while making dry etching of the lowermost-layerinsulating film 111 with the photoresist film as the mask. And, etchingback of the etching stopper film 109 is performed by dry-etching.

After that, etching to the middle of the silicon substrate 101 isfurther performed while changing etching gas. For instance, etching tothe depth of not less than 10 μm to not more than 50 μm from the upperface of the silicon substrate 101 is performed. By making the depth notless than 10 μm, it is possible to connect certainly a periphery of theprotruding portion 141 with the large diameter plug 131. Further, bymaking the depth not more than 50 μm, it is possible to reduce amount ofprojection of the small diameter plug 119 to an inner portion of thesilicon substrate 101 from the main face of the silicon substrate 101.For this reason, it is possible to form an opening stably. The diameterof the opening is selected such that the diameter of the small diameterplug 119 becomes, for instance, degree of 1 to 5 μm. And then, residueof the photoresist film, or the antireflection film or residue caused byetching is removed.

Next, SiN film 137 of 20 nm is formed on the entire surface of the upperface of the silicon substrate 101 on which there is provided the openingcorresponding to the shape of the small diameter plug 119. Owing tothis, the SiN film 137 is formed on a side face and a bottom face of theopening.

And, a resist pattern (not shown in the drawings) with the opening,which opens corresponding to the shape of the connection plug 123, usingthe photolithography technique is formed upon applying newly anantireflection film and a photoresist on the lowermost-layer insulatingfilm 111. A position where the connection plug 123 of an upper portionof the diffusion layer 105 is provided is opened while performing dryetching of the lowermost-layer insulating film 111 with the photoresistfilm as the mask. And, etching back of the etching stopper film 109 isperformed by dry-etching to expose the upper face of the diffusion layer105. Thus the holes to form the small diameter plug 119 and theconnection plug 123 are obtained.

Next, W (tungsten) film as metal film is formed by CVD technique on theentire surface of the upper face of the silicon substrate 101. The filmthickness of the W (tungsten) film is set to the film thickness in astate where, by matching to the diameter of both of the connection plug123 and the small diameter plug 119, the both can be embedded in theconnection plug 123 and the small diameter plug 119. For instance, thefilm thickness of W (tungsten) is set to degree of 1 μm. Then, W(tungsten) film and the SiN film 137 on the lowermost-layer insulatingfilm 111 are removed by CMP (Chemical Mechanical polishing). Thus, thesmall diameter plug 119 and the connection plug 123 are formedsimultaneously (FIG. 2A).

Next, the first interconnect layer insulating film 113 is provided onthe entire surface of the upper face of the silicon substrate 101. Thefirst interconnect layer insulating film 113, as shown in FIG. 2B, has alayered structure formed with an insulating film for interconnect 112and an insulating film for plug 114.

Firstly, the insulating film for interconnect 112 of 300 nm to be anunder layer of the first interconnect layer insulating film 113 isformed, while coating the entire surface of the upper face of thesilicon substrate 101. The insulating film for interconnect 112 can beset to a low dielectric constant film such as for instance L-Ox™ or thelike. At this time, it may be suitable that there is provided SiCN filmas Cu diffusion preventing film on the lowermost-layer insulating film111. Further, it may be suitable that SiO₂ film of 100 nm is formed onthe low dielectric constant film. Next, an antireflection film and aphotoresist are applied on the entire surface of the upper face of thesilicon substrate 101 upon using photolithography technique, resultingin forming resist pattern for interconnect trench on the photoresist.Then, an opening for manufacturing the first interconnect 121 is formedwhile performing etching of the insulating film for interconnect 112with the photoresist as a mask. Next, the photoresist and theantireflection film are removed by ashing.

After that, by using a sputtering technique, TaN film of 30 nm as for abarrier metal film is formed, and Cu film of 100 nm for a seed is formedon the TaN film. Next, a Cu film of 700 nm is formed by an electrolyticplating technique, subsequently to become the first interconnect 121 isformed by CMP technique. After that, just as the small diameter plug 119and the connection plug 123 are formed, the first interconnect 121 isformed while removing Cu film and barrier metal film on the insulatingfilm for interconnect 112.

After that, the insulating film for plug 114 constituting an upper layerof the first interconnect layer insulating film 113 is formed on theinsulating film for interconnect 112 by usual interconnect manufacturingprocess. The connection plug 122 to connect to the first interconnect121 is formed in the insulating film for plug 114. Then, the pad 125 andthe bump 127 to connect to the connection plug 122 are formed in thisorder. Material of the pad 125 may be set to, for instance, Al, Cu, Ni,TiN, or the like. Further, material of the bump 127 may be set to, forinstance, Au, solder, or the like.

It should be noted that there may be further formed an upper layer ofthe predetermined number of interconnect layer or the like on the upperportion of the first interconnect layer insulating film 113.

Next, an adhesive layer 115 is formed on the upper face of the siliconsubstrate 101 to attach a supporting component 117 (FIG. 2B). Forinstance, an adhesive tape is used as the adhesive layer 115. Theadhesive tape is composed of a base material and the adhesive layerformed on its both sides. As the base material composing the adhesivetape, for instance, polyolefin resin, polyester resin or the like isused. As the adhesive composing the adhesive tape, for instance, anacrylic emulsion adhesive, an acrylic solvent adhesive, a polyurethaneadhesive or the like is used.

In addition, materials of the supporting component 117 may be materialsprovided with durability to heat, agent, external force or the like inthe process of thinning processing or the like of the silicon substrate101 by grinding rear surface described later, thus the materials can beset to, for instance, quarts, Pyrex™ or the like of glasses. Further, itmay be set to materials in addition to glass. For instance, materials ofplastics or the like such as acrylic resin and so forth may be used.

Next, grinding the rear surface of the silicon substrate 101 isperformed. Grinding the rear surface is performed by mechanicalpolishing. Although thickness of the silicon substrate 101 aftergrinding can be appropriately selected within the range that a bottomportion of the small diameter plug 119 is not exposed; for instance, thethickness can be set to 50 to 200 μm. Then, the antireflection film andthe photoresist are formed in this order on the rear surface of thesilicon substrate 101; and the resist pattern (not shown in thedrawings) is formed in which an opening to form the large diameter plug131 is provided, while using the photolithography technique. The siliconsubstrate 101 is selectively dry-etched with the photoresist film as themask, after that, the opening 139 is provided at the position where thelarge diameter plug 131 should be provided.

The opening 139 has a shape, in which, the opening 139 is headed towardthe main face from the rear surface of the silicon substrate 101, upperface of the silicon substrate 101 is positioned in a lower portion thanvicinity of the main face of the silicon substrate 101. Further, theopening 139 is provided on a bottom portion of the protruding portion141, and the upper face of the opening 139 is positioned at an upperportion than the bottom face of the small diameter plug 119. The SiNfilm 137 is provided on the surface of the small diameter plug 119.Etching conditions at the time the above described silicon substrate 101is performed dry etching are the conditions where selectivity between asilicon film and the SiN film 137 is set to high condition, therefore,when the opening 139 is formed, the small diameter plug 119 is notremoved, but the silicon substrate 101 of side face outer periphery ofthe small diameter plug 119 is selectively removed. Owing to this, theopening 139 is formed with a shape including the bottom face of thesmall diameter plug 119. Further, a part of the small diameter plug 119is exposed to outside of the silicon substrate 101, thus the protrudingportion 141 is formed.

Next, an electrodeposited insulating film 129 is provided on the rearsurface of the silicon substrate 101 (FIG. 2C). At this time, theelectrodeposited insulating film 129 is selectively formed on the rearsurface of the silicon substrate 101, and the bottom face and side faceof the opening 139. The surface of the protruding portion 141 is coatedwith the insulative SiN film 137, so that the electrodepositedinsulating film 129 is not formed at outer side of the small diameterplug 119. The film thickness of the electrodeposited insulating film 129is set to, for instance, degree of 0.5 to 5 μm.

The electrodeposited insulating film 129 is made, for instance, anelectrodeposited polyimide film. It is possible to use cationicelectrodeposited polyimide coating and anionic electrodepositedpolyimide coating as materials of the electrodeposited polyimide film.Specifically, for instance, Elecoat PI manufactured by Shimizu corp. orthe like can be used. It should be noted that the material of theelectrodeposited insulating film 129 is not limited to polyimide, alsoit may be used another electrodeposited polymer coatings such as anepoxy containing electrodeposited coating, an acrylic containingelectrodeposited coating, fluorine containing electrodeposited coatingor the like. Heat-resisting property of the electrodeposited insulatingfilm 129 can be improved upon using the polyimide as the material of theelectrodeposited insulating film 129. For this reason, deterioration inmanufacturing process afterwards is appropriately suppressed, so that itis possible to realize configuration in which stable manufacturing witha high yield is achieved.

Formation of the electrodeposited insulating film 129 is performed insuch a way as, for instance, following process. The silicon substrate istaken as one side of electrode, and one side of electrode and anotherside of electrode are dipped within the liquid of an electrodepositedcoating. Then, predetermined potential is applied to the siliconsubstrate 101 and another side of electrode depending on electric chargeof the polymer within the electrodeposited coating. In such a way asabove, the polymer adheres on the surface of the silicon substrate 101.After the predetermined film thickness is obtained, the siliconsubstrate 101 is taken out from the coating to wash it in water. Afterthat, the electrodeposited insulating film 129 is formed on the rearsurface upon baking the silicon substrate 101.

Next, the etching back of the SiN film 137 is performed. Herewith, theSiN film 137 is removed at a leading end of the protruding portion 141to expose the surface of the small diameter plug 119. At this time, theelectrodeposited insulating film 129 is formed on the rear surface ofthe silicon substrate 101, therefore, the silicon substrate is notremoved, but the SiN film 137 is selectively removed. It should be notedthat although, in FIG. 1 and FIG. 2D, a configuration in which the wholeSiN film 137 in the protruding portion 141 is removed is exemplified,and it may be suitable that at least a portion including a plug bottomportion of the small diameter plug 119 is exposed.

Subsequently, through the electroless plating technique, the Ni film isgrown with the exposed portion of the small diameter plug 119 as thestarting point, the opening 139 is embedded and the bump is integrallyformed at the outside of the opening 139. Then, the large diameter plug131 is formed upon providing the Au plating film 133 on the surface ofthe bump (FIG. 2D).

At this time, formation of the large diameter plug 131 may be performedin such a way as to separate into two processes of embedding process ofthe opening 139 of the rear surface and bump forming process of the rearsurface.

After that, upon removing the adhesive layer 115 from the main face ofthe silicon substrate 101, the supporting component is removed, and thesemiconductor device 100 shown in FIG. 1 can be obtained.

Next, there will be described the effect of the semiconductor device 100shown in FIG. 1.

Firstly, in the semiconductor device 100, the through electrode 135 iscomposed of two plugs of the small diameter plug 119 and the largediameter plug 131. The protruding portion 141 at the end portion of thesmall diameter plug 119 is involved in the large diameter plug 131.

FIG. 7A and FIG. 7B are views schematically showing a configuration ofthe through electrode composed of two plugs with different thickness. Inrespective partial drawings, the upper view is a sectional view, and thelower view is a plan view. FIG. 7A is a view showing configuration ofthe through electrode 135 according to the present embodiment. Further,FIG. 7B is a view showing the through electrode 235 of the shape inwhich the small diameter plug 219 and the large diameter plug 231 areconnected in the plane face.

In the configuration of FIG. 7A, improvement of adhesion of both plugsby an anchor effect is a goal. For this reason, as shown in FIG. 7B, thethrough electrode can be realized as a bonded configuration as comparedto the case where between these end portions are only in contact witheach other. Further, selective growing from the rear surface of thesilicon substrate 101 makes it possible to form the large diameter plug131. For this reason, the configuration makes it possible to simplifythe manufacturing process. Further, reduction of contact resistancebetween both plugs is attained based on this configuration. For thisreason, it is possible to improve electrical characteristics of thesemiconductor device 100.

In addition, as shown in FIG. 7C, the through electrode 135 is composedof three plugs of the large diameter plug 131, and two small diameterplugs 119 involved in the large diameter plug 131, adhesion of the plugbased on the anchor effect is further improved, and more reduction ofthe contact resistance is attained.

It should be noted that it is not necessary for the small diameter plug119 to penetrate until rear surface side of the large diameter plug 131.Since depth of the protruding portion 141 can be made shallow,manufacturing of the small diameter plug 119 by embedding can beperformed stably.

Further, in the through electrode 135, the diameter of the smalldiameter plug 119 is smaller than the diameter of the large diameterplug 131. For this reason, it is possible to minimize the size of thefirst interconnect 121 electrically connecting to the small diameterplug 119. Further, this configuration can improve integration ofelements in the lowermost-layer insulating film 111. Consequently, thisconfiguration is an appropriate configuration for miniaturization of thewhole device.

Further, since the small diameter plug 119 can be manufactured at thesame time the connection plug 123 is manufactured, the configurationmakes it possible to simplify the manufacturing process and to reducethe manufacturing cost accompanied with simple process. Further, theinfluence of formation of the small diameter plug 119 on formationprocess of the transistor is small, thus, the configuration is aconfiguration that formation of the through electrode 135 gives a littledamages to the transistor.

Further, in the upper portion of the through electrode 135, the smalldiameter plug 119 is connected to the first interconnect 121 within thefirst interconnect layer insulating film 113 to be the lowermost-layerinterconnect, so that the configuration causes the through electrode 135not to protrude into the first interconnect layer insulating film 113.For this reason, this configuration can improve the interconnect densityin the first interconnect layer insulating film 113. Consequently,influence of installation of the through electrode 135 on constitutionof the circuit is small, so that the semiconductor device 100 has thefreedom of selection with respect to elements or interconnectarrangement, and further makes it possible to reduce dead space of thefirst interconnect layer insulating film 113 and to enhance integrationof the first interconnect 121.

Further, in the semiconductor device 100, there is selectively providedthe electrodeposited insulating film 129 at the region other than thesurface of the protruding portion 141 of the inner surface of theopening 139. For this reason, in the process after forming the largediameter plug 131, since it is possible to use the electrodepositedinsulating film 129 as the protective film, it is not necessary to formthe resist pattern for formation of the large diameter plug 131 on therear surface of the silicon substrate 101. For this reason, theconfiguration makes it possible to manufacture the large diameter plug131 stably in the simple process.

Next, configuration of the through electrode 135 composed of the smalldiameter plug 119 and the large diameter plug 131 is further describedas compared with configuration of the conventional through electrode.FIGS. 8A and 8B are sectional views schematically showing configurationof the through electrode. FIG. 8A is a view schematically showingconfiguration of the through electrode 135 according to the presentembodiment. Further, FIG. 8B is a view schematically showingconfiguration of the conventional through electrode 235.

As shown in FIG. 8B, the conventional through electrode 235 is composedof one thick plug, and comes into contact with the interconnect 253 onits upper surface. For this reason, the conventional through electrodehas tendency that the area of the interconnect 253 on the upper portionof the through electrode 235 becomes relatively large. Further, in thelayer of the interconnect 253 coming into contact with the throughelectrode 235, an interconnect 254 except for the interconnect 253coming into contact with the through electrode 235 cannot be provided inthe vicinity of the through electrode 235. For this reason, as indicatedby the arrow in the drawing, it has been possible to form theinterconnect 254 other than the interconnect 253 coming into contactwith the through electrode 235, only within the region distant from theupper face of the through electrode 235 and its vicinity. Consequently,there is still room for further improvement relative to enhancement ofintegration of the interconnect 254 other than the interconnect 253coming into contact with the through electrode 235.

On the contrary, as shown in FIG. 8A, in the through electrode 135according to the present embodiment, the through electrode comes intocontact with the interconnect 153 on the upper face of the smalldiameter plug 119. For this reason, it is possible to minimize the crosssectional area of the interconnect 153 on the upper portion of the smalldiameter plug 119. Further, the plug connecting the interconnect 153 isof the small diameter plug 119. For this reason, as indicated by thearrow in the drawing, the region where the interconnect 154 other thanthe interconnect 153 coming into contact with the small diameter plug119 can be formed is wide. For this reason, it is possible to enhanceintegration of the interconnect 154 other than the interconnect 153coming into contact with the small diameter 119. Further, it is possibleto reduce electrical resistance by increasing diameter of the plug otherthan vicinity of the interconnect layer, while securing sufficientlyinterconnect density by minimizing diameter of the plug in the vicinityof the interconnect layer.

Further, as described previously while using FIG. 7A and FIG. 7B, in thethrough electrode 135 in FIG. 8A, the configuration illustrates that apart of the small diameter plug 119 is put into the large diameter plug131. For this reason, even though two plugs are used, different fromconfiguration of FIG. 8B, contact resistance between these plugs issufficiently small as compared to configuration of FIG. 7B, thus theconfiguration has excellent characteristics as the through electrode.

It should be noted that although there is not shown in FIG. 1, in thesemiconductor device 100, configuration of the upper layer of the firstinterconnect layer insulating film 113 can be selected appropriatelydepending on designing of the device. An interconnect layer or the likemay be further formed on the upper portion of the first interconnectlayer insulating film 113.

For instance, FIG. 10 is a sectional view schematically showingconfiguration of the semiconductor device in which the semiconductordevice has the layered structure formed with interconnect layers.Although configuration of the semiconductor device in FIG. 10 is thesame as the semiconductor device 100 shown in FIG. 1 basically; thereare formed a lowermost-layer insulating film 111, the first interconnectlayer insulating film 113, and in addition thereto, an insulating layer161 and an insulating layer 163 are further formed with the layeredstructure. An interconnect 165 and connection plug 167 are formed in theinsulating layer 161. An interconnect 169 and connection plug 171 areformed in the insulating layer 163.

As shown in FIG. 10, the through electrode 135 according to the presentembodiment, there is provided the small diameter plug 119 with smallcross sectional area at the main face side, and the small diameter plug119 is connected to the first interconnect 121 provided at lower layerin the formed body. For this reason, it is possible to enhanceintegration of the interconnect of the upper layer.

Further, FIG. 11 is a sectional view schematically showing anotherconfiguration of the semiconductor device in which the semiconductordevice has the layered structure formed with the interconnect layers. Asshown in FIG. 11, the small diameter plug 119 is connected to the firstinterconnect 121, therefore, this configuration is excellent in thefreedom of design of the upper layer than the first interconnect 121.For instance, this makes it possible to bring configuration in which thethrough electrode 135 is not connected to the bump 127, or to bring aconfiguration in which the through electrode 135 is connected to thebump 127 through an interconnect, which is not shown in the drawing,without forming the bump 127 just above the through electrode 135.

Further, in the semiconductor device according to the present embodimentand the following embodiment, as a mode in which a part of the smalldiameter plug 119 composing the through electrode 135 is involved in thelarge diameter plug 131, for instance, a mode in which a part of crosssection of the small diameter plug 119 is involved and a mode in whichthe whole cross section is involved are indicated. FIGS. 12A and 12B arecross sectional views schematically showing such a configuration of thethrough electrode 135. FIG. 12A is a view showing configuration in whichthe whole of cross section of the small diameter plug 119 is involved inthe large diameter plug 131. Further, FIG. 12B is a view showing aconfiguration in which a part of the cross section of the small diameterplug 119 is involved in the large diameter plug 131. The shape of aconcave portion formed on the large diameter plug 131 is differentdepending on a way in a state where the small diameter plug 119 isinvolved.

As shown in FIGS. 12A and 12B, a configuration in which the smalldiameter plug 119 comes into contact with the large diameter plug 131with the plurality of faces thereof can be obtained, upon bringing atleast a part of cross section of the small diameter plug 119 to beinvolved in the large diameter plug 131. For this reason, it is possibleto improve adhesion between the small diameter plug 119 and the largediameter plug 131 as compared with configuration described above whileusing FIG. 7B. Further, as shown in FIG. 12A, it is possible to furtherimprove adhesion between the both components upon adopting aconfiguration in which the whole cross section of the small diameterplug 119 is put into the large diameter plug 131 to be involved therein.

In the following embodiments, there will be mainly illustrated about thepoint different from the first embodiment.

Second Embodiment

FIG. 3 is a cross-sectional view schematically showing a configurationof the semiconductor device according to the present embodiment. In thesemiconductor device 102 shown in FIG. 3, the upper face of the largediameter plug 131 matches the upper face of the silicon substrate 101,that is, the main face of the silicon substrate 101. In addition, in thesemiconductor device 102, SiN film 143 is formed on a side face of thelarge diameter plug 131 and SiN film 145 is formed on a rear surface ofthe silicon substrate 101 instead of the electrodeposited insulatingfilm 129 in the silicon substrate 101 shown in FIG. 1.

Next, there will be illustrated a method for manufacturing thesemiconductor device 102. FIGS. 4A to 4D are cross-sectional viewsschematically showing the manufacturing process of the semiconductordevice 102 shown in FIG. 2.

Firstly, a resist pattern (not shown in the drawings) having an openingcorresponding to the shape of the large diameter plug 131 using thephotolithography technique is formed upon applying the antireflectionfilm and the photoresist to the silicon substrate 101 in this order. Theopening for providing the large diameter plug 131 is formed, whileperforming dry etching of the silicon substrate 101 with thisphotoresist film as the mask. At this time, the opening depth isappropriately selected, and the opening depth may be set to, forinstance, not less than 50 μm to not more than 200 μm. Then, thephotoresist and the antireflection film are removed.

Next, the SiN film 143 of 100 nm is formed on the entire surface of theupper face of the silicon substrate 101 on which the openingcorresponding to the shape of the large diameter plug 131 is provided.Then, the SiO₂ film 147 covers the entire surface of the main face ofthe silicon substrate 101 by applying SOG (spin on glass) so as to embedthe opening. Next, the SiO₂ film 147 formed on the region other than theopening is removed to expose the upper face of the SiN film 143. Next,the SiN film is formed as for the etching stopper film 109, and theupper face of the SiO₂ film is coated with the etching stopper film 109(FIG. 4A).

Next, like the first embodiment, there are provided the isolation film103, the diffusion layer 105 and the gate electrode 107. Further, likethe first embodiment, the lowermost insulating film 111 is formed,followed by being formed simultaneously the small diameter plug 119penetrating the lowermost layer insulating film 111 and the connectionplug 123 (FIG. 4B). It should be noted that, in the semiconductor device102, it is possible to adopt a configuration where the small diameterplug 119 is put into the SiO₂ film 147 with the depth of, for instance,of 1 to 50 μm.

Then, like the first embodiment, the first interconnect layer insulatingfilm 113, the first interconnect 121, the connection plug 122, the pad125 and the bump 127 are formed. Then, the main face side of the siliconsubstrate 101 is fixed to the surface of the supporting component 117via the adhesive layer 115.

Next, the grinding rear surface of the silicon substrate 101 isperformed to expose the lower face of the SiN film 143 provided on thebottom face of the SiO₂ film 147. At this time, it may be suitable thatthe SiO₂ film 147 is further exposed while advancing grinding rearsurface. The dry etching of the rear surface of the silicon substrate101 is further performed with the SiN film 143 or the SiO₂ film 147 asthe mask. Owing to this, a protruding portion 142 is formed on a rearsurface side of the silicon substrate 101. Then, the SiN film 145 isformed on the entire surface of the rear surface side of the siliconsubstrate 101. Then, the SiN in the rear surface of the siliconsubstrate 101 is removed by performing CMP to expose a lower face of theSiO₂ film 147 in the protruding portion 142 (FIG. 4C).

Next, the SiO₂ film 147 is removed by wet etching. A thick HF watersolution, such as for instance, 40 to 49 wt % is used as for an etchingsolution. At this time, the SiO₂ film 147 is selectively removed becausethe etching stopper film 109 is provided on the upper face of the SiO₂film 147 and the SiN film 143 is provided on the side face of the SiO₂film 147. In such a way as above, the opening having the shape of thelarge diameter plug 131 is obtained and the protruding portion 141 isexposed.

Then, like the first embodiment, the etching back of the SiN film 137 isperformed, a Ni film is grown by electroless plating technique with anexposed portion of the small plug 119 as a starting point, followed byembedding the opening 139, and a bump is formed integrally at outside ofthe opening 139. Then, the large diameter plug 131 is formed, uponproviding the Au plating film 133 on the surface of the bump (FIG. 4D).

Then, the supporting component 117 is removed by separating the adhesivelayer 115 from the main face of the silicon substrate 101 and thesemiconductor device 102 shown in FIG. 3 is obtained.

Next, there will be described effects of the semiconductor device 102shown in FIG. 3. The semiconductor device 102 has the following effectsin addition to the effect of the semiconductor device 100 described inthe first embodiment.

The semiconductor device 102 has a configuration where the SiO₂ film 147is formed on the position of the large diameter plug 131, before formingthe transistor. Owing to this, the configuration makes it possible toperform a deep etching to form the large diameter plug 131 beforeforming elements. Accordingly, the SiO₂ film 147 may suitably be removedafter grinding rear surface, on the occasion of providing the openingfor forming the large diameter plug 131 on the rear surface side.Consequently, the large diameter plug 131 can be formed withoutperforming the deep etching of the silicon substrate 101 after formingthe transistor. Owing to this, the transistor or the like receives alittle damage caused by plasma irradiation or the like, so thatreliability is further improved.

In addition, in the semiconductor device 102, the protruding portion 142is formed on the rear surface side of the silicon substrate 101. Owingto this, it is aimed that the Ni film is suppressed to come into contactwith the silicon substrate 101 at the side face of the large diameterplug 131 or the bump. For this reason, the configuration is excellent inreliability.

In addition, on the occasion of grinding rear surface of the siliconsubstrate 101, there is adopted a configuration where the SiO₂ film 147and the silicon substrate 101 are ground simultaneously. Owing to this,roughening of the rear surface of the through electrode 135 caused by adifference of grinding ratio is suppressed as compared to the case wherea metal film and the silicon substrate 101 are ground simultaneously.

On the other hand, in the conventional through electrode, for instance,as described in Masataka Hoshino et al., grinding the rear surface isperformed after forming electrodes. For this reason, the siliconsubstrate and the metal film should be ground simultaneously on theoccasion of grinding the rear surface. However, the grinding ratiobetween these components is relatively large and, therefore, rougheningthe rear surface of the through electrode was easy. In addition, themetal film has high ductility and, therefore, shear drops are generatedat the periphery of the rear surface electrode, and the shear dropsadhere on the Si face. In the case that a metal such as Cu or the like,which is able to relatively diffuse readily in the Si, is included, insome cases, the metal is diffused in the silicon substrate. For thisreason, in some cases, reliability of the elements such as thetransistor or the like deteriorated.

On the contrary, in the semiconductor device 102 shown in FIG. 3, thereis adopted a configuration where the SiO₂ film 147 and the siliconsubstrate 101 are ground simultaneously in grinding the rear surface,therefore, control of grinding the rear surface is easy, theconfiguration makes it possible to grind the rear surface stably, andthe configuration makes it possible to have the flat rear surface. Inaddition, the configuration makes it possible to form the large diameterplug 131 stably. In addition, the side face and the bottom face of thelarge diameter plug 131 are coated with the SiN film 143 and the SiNfilm 145 respectively, therefore, the configuration where diffusion ofthe metal included in the large diameter plug 131 into the siliconsubstrate 101 is suitably suppressed is realized. Owing to this, theconfiguration, which is excellent in reliability of the elements such asthe transistor or the like, is realized. In addition, the configurationis a configuration in which it is possible to reduce the manufacturingcost on the occasion of grinding rear surface.

It should be noted that, on the occasion of manufacturing thesemiconductor device 102 according to the present embodiment, asdescribed above, the dry etching of the silicon substrate 101 isperformed to form the opening (not shown in FIG. 4A) for providing thelarge diameter plug 131. It is possible to utilize the process fordicing, on the occasion of manufacturing a plurality of semiconductordevices 102 on the wafer simultaneously.

FIGS. 9A and 9B are plan views schematically showing the configurationof the wafer 155 during manufacture of the semiconductor device 102.FIG. 9A indicates the wafer 155 before dicing, and a dicing line 157 isindicated with a dotted line in the drawing. In addition, FIG. 9B is adrawing in which the vicinity of the dicing line 157 of FIG. 9A isenlarged. It should be noted that the wafer 155 corresponds to thesilicon substrate 101 in the semiconductor device 102.

As shown in FIGS. 9A and 9B, the plurality of the semiconductor devices102 are formed on the surface of the wafer 155. In the formation of thesemiconductor device 102, a trench for dicing is formed on the dicingline 157 in the silicon substrate 101 at the same time as the formationof the large diameter plug 131. After that, the semiconductor device 102is manufactured with the process described above. At this time, anopening formed in the vicinity of the dicing line 157 becomes a throughtrench 159 due to grinding rear surface. Then, plural semiconductordevices 102 are obtained in such a way that the whole wafer fracturesalong the dicing line 157 caused by the fact that the whole wafer isdrawn, or it causes the whole wafer to deform while pressing it to aroller or the like.

In this method, in the wafer 155 in which the plurality of thesemiconductor device 102 are formed, it is possible to provide thethrough trench 159 between forming regions of the semiconductor device102. The wafer 155 on the inside of the through trench 159 is removed,therefore, the forming region of the through trench 159 can be thinnerthan another region. Owing to this, it is possible to perform divisionof the wafer 155 surely, by making this part a region of dicing.

In addition, the method can form the through trench 159 in the vicinityof the dicing line 157. For this reason, the configuration in which thedicing is easy to perform can be realized. The through trench 159 isobtained at the same time as the opening for forming the large diameterplug 131, therefore, it is not necessary to follow the other process tomanufacture the through trench 159. Owing to this, the configuration isa configuration in which the low cost dicing is possible. For thisreason, it is possible to include the dicing process into the rearsurface process without increasing cost. In addition, it is possible toobtain a suitable scribing region for condition of the dicing uponadjusting an interval and size of the through trench 159. For thisreason, the dicing with narrow pitch is possible, upon improvingintegration density of the through trench 159, for instance. That is, inthis dicing method, it is possible to very minimize a dicing width andtherefore it is possible to increase the number of chips to be takenfrom one wafer as compared with a process using usual blade.

Third Embodiment

FIG. 5 is a cross-sectional view schematically showing configuration ofthe semiconductor device according to the present embodiment. In asemiconductor device 104 shown in FIG. 5, there is provided an SiO₂ ring151 to cover the periphery of the large diameter plug 131. The SiO₂ ring151 is provided in such a way as to come into contact with the SiN film143 in the side face of the large diameter plug 131. The side face ofthe SiO₂ ring 151 comes into contact with the silicon substrate 101 viathe SiN film 143. In addition, like the second embodiment, the SiN film149 is provided on the rear surface of the silicon substrate 101.

Next, there will be described a method for manufacturing thesemiconductor device 104. FIGS. 6A to 6D are cross-sectional viewsschematically showing the manufacturing process of the semiconductordevice 104 shown in FIG. 5.

Firstly, the configuration shown in FIG. 6A is formed. At the beginning,the antireflection film and the photoresist are applied on the siliconsubstrate 101 in this order, a resist pattern (not shown in thedrawings) having a cylindrical ring shaped opening corresponding to theshape of the SiO₂ ring 151 is formed using the photolithographictechnique. The opening for providing the SiO₂ ring 151 is formed whileperforming the dry etching of the silicon substrate 101 with thephotoresist as the mask. At this time, depth of the opening isappropriately selected, for instance, the depth of the opening may beset to not less than 50 μm to not more than 200 μm. Then, thephotoresist film and the antireflection film are removed.

Next, the SiN film 143 of 100 nm is formed on the entire upper face ofthe silicon substrate 101 on which the opening corresponding to theshape of the SiO₂ ring. Then, the SiO₂ film is applied using SOG (spinon glass) to the entire face of the main face of the silicon substrate101 so as to embed the opening. Next, the SiO₂ film formed on the regionother than the opening is removed by CMP to expose the upper face of theSiN film 143. In such a way as above, the SiO₂ ring is obtained. Then,the SiN film as for the etching stopper film 109 is formed, and theupper face of the SiO₂ film 147 is coated with the etching stopper film109.

Next, like the first embodiment, there are provided the isolation film103, the diffusion layer 105 and the gate electrode 107. Further, likethe first embodiment, the lowermost layer insulating film 111 is formed,and then the small diameter plug 119 and the connection plug 123penetrating the lowermost layer insulating film 111 are formedsimultaneously. It should be noted that, in the semiconductor device102, the configuration in which the small diameter plug 119 is put intothe silicon substrate 101 with a depth of, for instance, 1 to 50 μm canbe realized.

Next, configuration shown in FIG. 6B is formed. First, like the firstembodiment, the first interconnect layer insulating film 113, the firstinterconnect 121, the connection plug 122, the pad 125 and the bump 127are formed. Then, the main face is fixed on the surface of thesupporting component 117 via the adhesive layer 115.

Next, like the first embodiment, grinding the rear surface of thesilicon substrate 101 is performed. Also, in the present embodiment,thickness of the silicon substrate 101 after grinding may be set to, forinstance, degree of 50 to 200 μm.

Next, the configuration shown in FIG. 6C is formed. At the beginning,the SiN film 149 of 20 nm is formed on the entire rear surface of thesilicon substrate 101 after grinding.

Then, the antireflection film and the photoresist are applied on therear surface of the silicon substrate 101 in this order, and then theresist pattern (not shown in the drawings) in which the inside of theSiO₂ ring 151 is opened is formed using the photolithographic technique.A wet etching of the rear surface of the silicon substrate 101 isfurther performed with the photoresist film as the mask. At this time,the wet etching is performed using, for instance, thick nitric fluoricacid. Owing to this, the silicon substrate 101 of the region surroundedby the SiO₂ ring 151 is removed, and the opening 139 is formed at therear surface side of the silicon substrate 101. In addition, theprotruding portion 141 is exposed in the opening 139.

Next, the configuration shown in FIG. 6D is formed. The etching back ofthe SiN film 149 is performed, after removing the photoresist and theantireflection film. At this time, the SiN film 137 of the leading edgeof the small diameter plug 119 is also removed. Then, TiW film and Cufilm as a barrier metal film are formed in this order on the entire rearsurface of the silicon substrate 101 using the sputtering technique.Then, the photoresist in which the opening 139 is opened is provided, onthe rear surface of the silicon substrate 101, followed by embedding theopening 139 while causing the Ni film to grow due to the electrolyticplating technique, and the bump is integrally formed at the outside ofthe opening 139. Then, the Au plating film 133 is provided on thesurface of the bump to obtain the large diameter plug 131. It should benoted that a rear surface interconnect may be formed at the same time asformation of the large diameter plug 131.

Then, the photoresist is removed, and the barrier metal film of thesurface of the silicon substrate 101 is removed by the wet etching.Then, the supporting component 117 is removed upon separating theadhesive layer 115 from the main face of the silicon substrate 101,thus, the semiconductor device 104 shown in FIG. 5 is obtained.

Next, there will be described the effects of the semiconductor device104 shown in FIG. 5. The semiconductor device 104 has the followingeffects in addition to the effect of the semiconductor device 100(FIG. 1) described in the first embodiment.

In the semiconductor device 104, the SiO₂ ring 151 is formed laterallyof the through electrode 135 in the silicon substrate 101. It ispossible to reduce a parasitic capacitance upon providing a thick wallof the SiO₂ around the large diameter plug 131. Consequently, it ispossible to speed up operation of the semiconductor device.

In addition, the SiO₂ ring 151 is provided within the silicon substrate101 before forming the elements such as the transistor or the like. Forthis reason, like the case of the second embodiment, the configurationin which deterioration of reliability of the elements caused byformation of the SiO₂ ring 151 is suppressed is realized.

It should be noted that, in the semiconductor device 104, the SiO₂ ring151 is formed laterally of the large diameter plug 131, however, thematerial of the ring may also be set to materials in addition to theSiO₂, if the material is the insulating material having durability toheating in the element formation process after the process. In addition,a cross-sectional shape of the SiO₂ ring 151 is not limited to acylindrical ring if it is closed, but, for instance, the SiO₂ ring 151may suitably be a ring shaped tubular body whose cross section is arectangle.

In addition, also in the semiconductor device 104 according to thepresent embodiment, like the case of the semiconductor device (FIG. 3)described in the second embodiment, the SiO₂ ring 151 is formed in thevicinity of the dicing line 157 of the wafer 155 in addition to the sideof the large diameter plug 131, owing to this, it is possible to realizeconfiguration excellent in dicing property.

As above, there have been described embodiments of the invention.However, of course, the present invention is not limited to the abovedescribed embodiments, and the person skilled in the art is capable ofchanging the above described embodiment within the scope of the presentinvention.

For instance, in the embodiment described above, the silicon substrateis used as for the semiconductor substrate, however, a compoundsemiconductor substrate such as GaAs substrate or the like may suitablybe used.

In addition, in the above described embodiment, W (tungsten) is used asfor the material of the small diameter plug 119, however, another metalwith high conductivity may suitably be used. For instance, metals suchas Cu, Al, Ni, polysilicon or the like may suitably be used.

In addition, in the above described embodiment, there has beenillustrated a configuration in which the small diameter plug 119composing the through electrode 135 is connected to the firstinterconnect layer insulating film 113, however, there may be adopted aconfiguration, in which the small diameter plug is connected to a lowerlayered interconnect layer to be an upper portion upper than the firstinterconnect layer insulating film 113, which resides upper than thesecond interconnect layer.

Further, in the embodiment described above, there has been exemplified aconfiguration in which one small diameter plug 119 is put into the upperface of one large diameter plug 131, however, as shown in FIG. 7C, aconfiguration in which more than two small diameter plugs 119 are putinto one large diameter plug 131 is possible. Owing to this, this makesit possible to further achieve anchor effect surely. Consequently, thismakes it possible to be further reliable electrical contact between thesmall diameter plug 119 and the large diameter plug 131.

Further, there has been exemplified the case where both the smalldiameter plug 119 and the large diameter plug 131 composing the throughelectrode 135 are cylinders, however, if two cross sectional areas ofrespective plugs are different from each other, it is not limited toconfigurations where cylinders with respective different diameters arecombined. The small diameter plug 119 or the large diameter plug 131 canbe formed with columnar body, and, for instance, the shape thereof maysuitably be a cylinder, an elliptical cylinder or a square column inwhich area of an upper face and bottom face are approximately identicalwith each other. Further, the shape of the plug may suitably be a shapeof a frustum of circular cone, a frustum of an elliptical cone, or afrustum of a pyramid with no leading end on an upper face. Further, thecolumnar body may suitably be a stripe shape stretching in onedirection.

Further, in the embodiment described above, also there can be adopted aconfiguration in which the upper face of the large diameter plug 131 ispositioned at lower portion of the main face of the silicon substrate101, in addition thereto, it may be possible to adopt a configurationmaking it possible to provide the large diameter plug 131 acrossvicinity of the main face from the rear surface of the silicon substrate101. Further, even though the upper face of the large diameter plug 131is somewhat protruded from the main face of the silicon substrate 101,the configuration may be suitable if the large diameter plug 131 isinsulated on the upper face of the large diameter plug 131.

Further, in the embodiment described above, the adhesive layer 115 andthe supporting component 117 are separated from the main surface of thesilicon substrate 101, however, the adhesive layer 115 and thesupporting component 117 are not separated, but they may form a part ofthe semiconductor device while remaining as they are if necessary.

It is apparent that the present invention is not limited to the aboveembodiment, that modified and changed without departing from the scopeand spirit of the invention.

1. A semiconductor device, comprising: a semiconductor substrate; aninsulating layer provided on a main surface of said semiconductorsubstrate; and a through electrode penetrating said semiconductorsubstrate and connected to a conductive component provided inside saidinsulating layer; wherein a cylindrical ring shaped insulating body isdisposed on an outer periphery of a side face of said through electrode,and wherein said through electrode comprises a first conductive plug ofa first material connecting with said conductive component, and a secondconductive plug of a second material different from the first material,which is provided in said semiconductor substrate, and which has a crosssectional area larger than a cross sectional area of said firstconductive plug.
 2. The semiconductor device according to claim 1,wherein said cylindrical ring shaped insulating body includes SiO₂. 3.The semiconductor device according to claim 1, wherein said cylindricalring shaped insulating body includes an SiO₂ layer and an SiN layer. 4.The semiconductor device according to claim 1, wherein a part of saidfirst conductive plug extends into said second conductive plug.
 5. Thesemiconductor device according to claim 1, wherein a plurality of saidfirst conductive plugs electrically connect to said single secondconductive plug.
 6. The semiconductor device according to claim 1,wherein said second conductive plug being formed from the rear surfaceof said semiconductor substrate to the vicinity of said main surface ofsaid semiconductor substrate.
 7. The semiconductor device according toclaim 1, wherein a part of said first conductive plug is put into saidsecond conductive plug.
 8. The semiconductor device according to claim1, wherein said second conductive plug is projected from a rear surfaceof said semiconductor substrate.
 9. The semiconductor device accordingto claim 1, wherein a cross sectional area of said through electrode inthe main face of said semiconductor substrate is smaller than a crosssectional area of said through electrode in a rear surface of saidsemiconductor substrate.
 10. A semiconductor device, comprising: asemiconductor substrate; a transistor formed layer provided on a mainface of said semiconductor substrate; an interconnect layer provided onan upper portion of said transistor formed layer; an upper interconnectlayer provided on an upper portion of said interconnect layer; a throughelectrode of a first material penetrating said transistor formed layerand said semiconductor substrate; a conductive plug of a second materialdifferent from the first material provided on another face of saidsemiconductor substrate opposite to said main face; and a cylindricalring shaped insulating body is disposed on an outer periphery of a sideface of said through electrode, wherein said through electrode connectsan interconnect formed in said interconnect layer and provided in saidtransistor formed layer, and said through electrode has a crosssectional area smaller than a cross sectional area of said conductiveplug.